Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 37 records · Page 2Linked to original sources

PubMed2004

Cerebral motor control in patients with gliomas around the central sulcus studied with spatially filtered magnetoencephalography.

OBJECTIVE: Application of spatially filtered magnetoencephalography (MEG) to investigate changes in the mechanism of cerebral motor control in patients with tumours around the central sulcus. METHODS: MEG records were made during a repetitive hand grasping task in six patients with gliomas around the central sulcus and in four control subjects. Power decreases in the alpha (8-13 Hz), beta (13-30 Hz), and low gamma bands (30-50 Hz) during the motor tasks (event related desynchronisation, ERD) were analysed statistically with synthetic aperture magnetometry. The tomography of ERD was superimposed on the individual's magnetic resonance image. RESULTS: beta ERD was consistently localised to the contralateral primary sensorimotor cortex (MI/SI) in control subjects, whereas the alpha and low gamma ERD showed considerable intersubject variability. beta ERD in patients during non-affected side hand movement was also localised to the contralateral MI/SI, but exclusively to the ipsilateral hemisphere during affected side hand movement. CONCLUSIONS: The altered pattern of ERD in the patient group during affected side hand movement suggests recruitment of diverse motor areas, especially the ipsilateral MI/SI, which may be required for the effective movement of the affected hand.

Adult↗

PubMed2004

[Novel strategy for thoracoabdomianl aortic aneurysm repair; intraoperative selective perfusion of the Adamkiewicz artery].

We report our method for delineating the Adamkiewicz artery using multidetector row computed tomography (MDCT) with selective perfusion using a distal perfusion cannula that is clinically available for off-pump coronary artery bypass (OPCAB). The tip of a distal perfusion catheter (Medtronic Quickflow, Minneapolis) designed for OPCAB was applicable for selective perfusion of the segmental arteries. The femoro-femoral venoarterial bypass was branched off into selective perfusion of the segmental arteries, using an independent roller pump and heat exchanger. Our method of visualization of the Adamkiewicz artery was MDCT scanning with injection of contrast medium directly into the proximal descending aorta: namely, "CT during aortography". Lower descending aorta to abdominal aorta (the range involving the aneurysm) was scanned in a cephalad-to-caudal direction using a detector collimation of 4 x 1.25 mm with a table speed of 9.4 mm/sec, pitch of 6, and image thickness of 1.25 mm. All images were reviewed on a workstation to investigate the continuity between the Adamkiewicz artery and its proximal segmental artery with paging, mulitplanar reformation and curved planar reformation. Distal perfusion cannulae of 2.0 mm in diameter were inserted into the respective intercostal arteries. 4-0 polyethylene sutures were placed to tourniquet the catheters. Segmental arteries were perfused with total flow of approximately 80 ml/min at a circuit pressure of 120 mmHg. Reattachment of the ninth intercostal arteries related to the Adamkiewicz artery was carried out. A total of 6 consecutive 6 patients with thoracoabdominal aortic aneurysm (TAAA) have undergone graft replacement by the methods described, since April 2002. All patients survived surgery without any neurological complications. This method is expected to minimize the ischemic time of the spinal cord and attenuate the reperfusion injury.

Aged↗

PubMed2003

Primary motor cortex stimulation within the central sulcus for treating deafferentation pain.

Nine patients with post-stroke pain, six with brachial plexus injuries, two with phantom limb pain, one with spinal cord injury, and one with brain stem injury were treated with a modified motor cortex stimulation (MCS) protocol. Preoperative pharmacological tests were performed with phentolamine, lidocaine, ketamine, thiopental, morphine, and placebo. We placed a grid electrode in the subdural space to decide upon the best stimulation point for pain relief over a few weeks with the purpose of determining the placement of a Resume electrode. In five patients, Resumes were implanted in the interhemispheric fissure to reduce lower extremity pain. In five other patients, Resumes were placed within the central sulcus to stimulate area 4 and area 3b. In addition, electrodes were also placed on the surface of the precentral gyrus. Fourteen of the 19 patients showed pain reduction (6 excellent, 3 good, and 5 fair) using the MCS with our results indicating area 4 within the central sulcus to be the optimal stimulation point for pain relief. We speculate that conventional method may sometimes fail to stimulate area 4 and that focal stimulation of the primary motor cortex within the central sulcus may improve the efficacy of this treatment. Our pharmacological tests show that patients with ketamine sensitivity seem to be good candidates for MCS. Test stimulation with a subdural multi-grid electrode and Resumes in the cetral sulcus were helpful in locating the best stimulation point for pain relief.

Adult↗

PubMed2003

Stereotactic radiofrequency ablation for sessile hypothalamic hamartoma with an image fusion technique.

BACKGROUND: Radiosurgery has been advocated as a primary treatment for hypothalamic hamartoma (HH), but it has a risk of damaging the surrounding structures and does not have an immediate effect for refractory epilepsy, endocrinological and mental disorders. METHOD: We report on a 13-year-old boy with a large and sessile HH who presented with intractable seizures, precocious puberty and aggressiveness. Stereotactic radiofrequency ablation (SRA) combined with an image fusion technique was performed to make a maximum ablative lesion within the HH via multiple trajectories. FINDINGS: After surgery, we observed rapid cessation of the gelastic seizures and aggressiveness. The ophthalmological function did not get worse, and the hypothalamopituitary function improved. INTERPRETATION: SRA in combination with an image fusion technique is a viable alternative treatment for HH, because it provides precise preoperative simulation and immediate improvement of symptoms can be obtained.

Adolescent↗

PubMed2003

Effect of rebamipide on prostaglandin receptors-mediated increase of inflammatory cytokine production by macrophages.

BACKGROUND: Rebamipide (Reb) is an anti-ulcer drug, and has unique properties such as anti-inflammatory action. We previously reported that prostaglandins (PGs) dramatically increased vascular endothelial growth factor (VEGF), a known angiogenic factor and a vascular permeable factor, by activated macrophages through specific PGE receptor and peroxisome proliferator-activated receptor gamma (PPARgamma, a nuclear receptor of PG) mediated process. Effects of PGs on the production of other cytokines such as interleukin (IL)-6 and IL-8 have been controversial. AIM: To clarify the anti-inflammatory roles of Reb, we examined the effect of Reb on PGE1- and 15-deoxy-Delta12, 14-PGJ2 (a potent PPARgamma ligand, 15d-PGJ2) -induced increase of VEGF production by macrophages. Additionally, effects of these PGs on the production of IL-6 and IL-8, and modulation of these actions by Reb were studied. METHODS: Phorbol 12-myristate 13-acetate-differentiated U937 cells were used as a human macrophage model (H-Mac). VEGF, IL-6, IL-8 and cAMP were measured by EIA. RESULTS: Reb suppressed PGE1-, but not 15d-PGJ2-, induced increase of VEGF production partially through decrease of cAMP formation. Reb suppressed PGE1 -, but not 15d-PGJ2-, induced increase of IL-6 and IL-8 production. CONCLUSION: Reb suppresses membrane, but not nuclear PG receptors mediated increase of inflammatory cytokine production, which may be involved in anti-ulcer action of this drug.

Alanine↗

PubMed2003

Association of SPINK5 gene polymorphisms with atopic dermatitis in the Japanese population.

BACKGROUND: Netherton's syndrome (NS) is an autosomal recessive disorder characterized by trichorrhexis invaginata ('bamboo hair'), congenital ichthyosiform erythroderma and an atopic diathesis. NS has recently been shown to be due to a defect in the SPINK5 gene, encoding LEKTI, a 15-domain serine protease inhibitor. SPINK5 maps to chromosome 5q31-q32, and has been suggested to be a locus predisposing to atopy in general. Recently, coding polymorphisms in SPINK5 exons 13 and 14 have been reported to be associated with atopy, asthma and atopic dermatitis (AD). OBJECTIVES: To examine whether these polymorphisms are also associated with AD in Japan. METHODS: We characterized eight polymorphisms in SPINK5 exons 13 and 14 in 124 Japanese patients with AD and 110 healthy controls. The polymorphisms we examined were IVS12-26C-->T, IVS12-10A-->G, 1103A-->G (Asn368Ser, in exon 13), 1156G-->A (Asp386Asn, in exon 13), 1188T-->C (His396His, in exon 13), IVS13-50G-->A, 1258G-->A (Glu420Lys, in exon 14) and IVS14+19G-->A. RESULTS: We found significant associations between seven of these polymorphisms and AD in Japanese patients. CONCLUSIONS: This study confirms the previous suggestion of an association between SPINK5 and AD.

Adolescent↗

PubMed2003

Association between blood indoxyl sulfate and carbonyl stress marker in hemodialysis patients.

BACKGROUND: Indoxyl sulfate (IS) is a protein-bound solute, which is progressively retained in blood according to the decline of renal function. However, clinical relevance of excess IS in hemodialysis (HD) patients remains unknown. PATIENTS AND METHODS: We measured serum IS and clinical parameters including pentosidine, carboxymethyllysine (CML) and homocysteine levels in 55 HD patients (age: 67 +/- 2 years, time on HD: 67 +/- 11 months, male/female = 30/25), and examined the relationship between IS and these data. RESULTS: Serum IS was markedly increased in HD patients (80.49 +/- 6.17 microg/ml) compared to normal range (< 1.9 microg/ml). IS was significantly and positively correlated with time on HD (p < 0.01), blood urea nitrogen (p < 0.01), beta2-microglobulin (p < 0.03), and protein catabolic rate (PCR) (p < 0.01). The patients with increased IS needed a higher erythropoietin dosage. Blood IS was positively correlated with pentosidine (r = 0.505, p < 0.01) and CML (r = 0.275, p < 0.05). In contrast, blood IS was not associated with nutritional and inflammatory parameters. A stepwise multiple regression analysis revealed that time on HD, PCR and pentosidine were significant determinants of IS. CONCLUSIONS: Serum IS was related to time on HD and dietary protein intake. Accumulated IS may be associated with enhanced carbonyl stress in chronic HD patients.

Adult↗

PubMed2002

Relationship between the stability of lysozymes mutated at the inside hydrophobic core and secretion in Saccharomyces cerevisiae.

The relationship between the stability of lysozymes mutated at the inside hydrophobic core and secretion was investigated to understand the optimal secretion of mutant lysozymes in the Saccharomyces cerevisiae. S91T mutant lysozyme increased in the methyl residue inside the core greatly increased the conformational stability. The secretion amount of S91T in S. cerevisiae increased greatly compared with wild-type lysozyme. On the other hand, I55V and T40S/I55V mutant lysozymes decreased in methyl residue inside the core brought about their unstable conformation. The secretion amounts of these unstable mutant lysozymes significantly decreased. In addition, the effect of glycosylation on the secretion of these mutants was investigated. The secretion amounts of glycosylated lysozyme S91T/G49N with stable hydrophobic core greatly increased compared with that of glycosylated lysozyme G49N, while those of mutant I55V/G49N and T40S/I55V/G49N with unstable hydrophobic core greatly decreased. These results indicate that the secretion amounts of mutant lysozymes increase in proportion to the hydrophobic core stabilities and that a similar good correlation was obtained with glycosylated lysozymes.

Anti-Infective Agents↗

PubMed2002

Yersinia pseudotuberculosis infection in breeding monkeys: detection and analysis of strain diversity by PCR.

In the last three decades, several monkeys reared in outdoor/indoor-outdoor breeding colonies and cages of the Primate Research Institute, Kyoto University, died of yersiniosis caused by Yersinia pseudotuberculosis, necessitating introduction of a method to detect the bacteria rapidly and thus allow preventive measures to be undertaken. A rapid nested polymerase chain reaction (PCR) method for identification of Y. pseudotuberculosis in fecal samples and a random amplified polymorphic DNA (RAPD)-PCR approach for distinguishing between bacterial strains were therefore developed. Yersinia pseudotuberculosis isolates from monkey specimens were found to be classifiable into several types. To determine the source of infection, hundreds of fecal samples of wild rats, pigeons, and sparrows were collected from around the breeding colonies and cages, and subjected to PCR analyses. Yersinia pseudotuberculosis was detected in 1.7% of the fecal samples of wild rats. The DNA fingerprints of the bacteria revealed by RAPD-PCR were the same as that of one strain isolated from macaques, suggesting the wild rat to be a possible source of infection.

Adhesins, Bacterial↗

PubMed2002

Review article: COX-2, prostanoids and colon cancer.

Epidemiological, experimental, and clinical studies have demonstrated that colon carcinogenesis may be prevented by nonsteroidal anti-inflammatory drugs (NSAIDs). Although controversy remains, recent studies, including ours, have revealed that NSAIDs suppress colon carcinogenesis at the adenoma stage where cyclooxygenase-2 (COX-2), a major molecular target in this action, is mainly expressed in interstitial cells but not in tumour cells. Therefore, it is unlikely that NSAIDs prevent colon cancer formation through modulating the functions of tumour cells. A more possible assumption is that NSAIDs suppress colon carcinogenesis through the inhibition of prostaglandin formation. However, the mechanisms by which prostanoids promote colon carcinogenesis have not been elucidated to date. A prostanoids act through both membrane receptors and nuclear receptors such as peroxisome proliferator receptor (PPAR) gamma or delta, one focus in this area is to investigate their roles in colon carcinogenesis, including the induction of growth factors.

Animals↗

PubMed2002

Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?

Using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and Adélie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. Flipper beating stopped during the latter part of ascent: at 29+/-9 % (mean +/- S.D.) of dive depth (mean dive depth=136.8+/-145.1 m, N=425 dives) in king penguins, and at 52+/-20 % of dive depth (mean dive depth=72.9+/-70.5 m, N=664 dives) in Adélie penguins. Propulsive swim speeds of both species were approximately 2 m s(-1) during dives; however, a marked increase in speed, up to approximately 2.9 m s(-1), sometimes occurred in king penguins during the passive ascending periods. During the prolonged ascending, oblique ascent angle and slowdown near the surface may represent one way to avoid the potential risk of decompression sickness. Biomechanical calculations for data from free-ranging king and Adélie penguins indicate that the air volume of the birds (respiratory system and plumage) can provide enough buoyancy for the passive ascent. When comparing the passive ascents for shallow and deep dives, there is a positive correlation between air volume and the depth of the dive. This suggests that penguins regulate their air volume to optimize the costs and benefits of buoyancy.

Air↗

PubMed2002

Ultrasound changes of the carpal tunnel in patients receiving long-term hemodialysis: a cross-sectional and longitudinal study.

BACKGROUND: Carpal tunnel syndrome (CTS) is one of the major problems of long-term hemodialysis (HD), but sometimes difficult to distinguish from uremic or diabetic neuropathy by clinical symptoms. PATIENTS AND METHODS: To evaluate the diagnosis of CTS more precisely, we examined the ultrasonographic alterations of the carpal tunnel and tendons of 90 wrists from 45 patients undergoing HD for more than 5 years. We measured the thickness of the palmar radiocarpal ligament (PRL), corresponding to the posterior wall of the carpal tunnel (CT), and the width of the CT, and compared those values with sensory (SCV), motor conduction velocity (MCV) of the median nerve and clinical symptoms. In addition, we longitudinally measured CT and PRL in the same patients for 5 years, and compared ultrasonographic changes and clinical parameters. RESULTS: A linear positive relationship was found between HD duration and PRL thickness (r = 0.43, p < 0.01) or CT width (r = 0.53, p < 0.01). CT diameter was negatively correlated with MCV (r = -0.30, p < 0.01) and SCV (r = -0.33, p < 0.04). PRL thickness was also inversely correlated with MCV (r = -0.44, p < 0.01) and SCV (r = -0.46, p < 0.01) of the median nerve, respectively. The wrists with clinical CTS and/or previous CTS surgery had significantly greater CT and PRL values compared to patients without CTS (CT: 6.1 0.2vs. 8.0+/-0.3 mm,p<0.01;PRL: 1.9+/-0.1 vs. 3.6 +/- 0.2 mm, p < 0.01). There was a significant increase in CT width from 6.2 +/- 0.2 to 7.1 +/- 0.2 mm (p < 0.01) and PRL thickness from 2.4 +/- 0.2 to 2.8 +/- 0.2 mm (p <0.01) during the 5-year observation, respectively. PRL thickness was constantly increased at the rate of 0.4 mm during the study. However, no significant association was found between the 5-year increases in CT and PRL distance and age, gender, the prevalence of diabetes, or laboratory parameters such as blood beta2-microglobulin, pentosidine and Kt/V(urea). CONCLUSION: Our data suggest that echographic evaluation of the wrist tissue thickness was useful to assess the progression of CTS. Serial measurements of the wrist by echography may be helpful to clarify the advance of subclinical CTS in patients receiving long-term HD.

Adult↗

PubMed2002

Measurement of des-gamma-carboxy prothrombin levels in hemodialysis patients positive for anti-hepatitis virus C antibody.

BACKGROUND: The prevalence of anti-hepatitis virus C (HCV) antibody is much higher in hemodialysis (HD) patients than in the normal population. Recently, blood des-gamma-carboxy prothrombin (PIVKA-II) has been demonstrated as a sensitive marker for the early detection of hepatocellular carcinoma (HCC). In this study, we measured blood PIVKA-II in HD patients positive for anti-HCV antibody or hepatitis B virus surface (HBs) antigen to examine if HD therapy may affect the measurement of PIVKA-II. PATIENTS AND METHODS: Ninety-four stable HD patients who had anti-HCV antibodies (n = 86) or HBs antigen (n = 8) without any evidence of HCC were enrolled in the study (age: 60 +/- 11 years, duration of HD: 17 +/- 10 years, male/female = 63/31). Five patients had liver cirrhosis and another 5 patients received warfarin treatment. We simultaneously measured serum PIVKA-II and alpha-fetoprotein (AFP), and compared the association between these markers and HCV RNA titer and laboratory parameters. RESULTS: Serum PIVKA-II became positive (> or = 40 mAU/ml) in only 5.6% (5/89) of patients without warfarin administration, ranging from 47 to 71 mAU/ml. Seventy out of 89 patients (78.7%) were below 20 mAU/ml. Serum PIVKA-II did not correlate with biochemical parameters including HCV RNA, while serum AFP was significantly correlated with serum AST (r = 0.21, p < 0.05), gamma-GTP (r = 0.21, p < 0.01) and platelet counts (r = -0.29, p < 0.01), respectively. In contrast, 5 patients receiving warfarin had an extremely high PIVKA-II value ranging from 1,930 to 19,900 mAU/ml. PIVKA-II was significantly and inversely correlated with the thrombotest value (r = -0.72, p = 0.01). CONCLUSION: The positivity of blood PIVKA-II in HD patients with hepatitis viremia was identical to that in patients without renal failure. Warfarin treatment dramatically increased serum PIVKA-II more than 1,000 mAU/ml. These findings suggested that HD treatment itself did not affect the measurement of PIVKA-II, but vitamin K deficiency can readily influence the PIVKA-II level in dialysis patients.

Adult↗

PubMed2002

Focal segmental glomerulosclerosis in a case of panhypopituitarism: a possible role of growth hormone treatment.

Panhypopituitarism manifests various symptoms including growth failure, hypothyroidism, adrenal insufficiency and hypogonadism. Dwarfism is an important problem in children with this condition, and long-term treatment with recombinant human growth hormone (GH) is usually required. We report a 24-year-old man with panhypopituitarism complicated by focal segmental glomerulosclerosis (FSGS). The patient had been treated with GH for hypopituitary dwarfism from 3 years of age. Proteinuria was initially noticed at 15 years of age and persisted despite cessation of GH supplementation at 18 years of age. A renal biopsy specimen showed glomerular hypertrophy and limited glomerulosclerosis, compatible with FSGS. To our knowledge, this is the first reported case of panhypopituitarism complicated by FSGS. Our case suggests that GH treatment for dwarfism may induce irreversible glomerular disease.

Adult↗

PubMed2002

Pseudohyperkalemia occurring in a patient with chronic renal failure and polycythemia vera without severe leukocytosis or thrombocytosis.

Pseudohyperkalemia is defined as a serum potassium concentration 0.4 mEq/l greater than the plasma concentration. The basis of this phenomenon is the release of intracellular potassium from platelets, leukocytes, or erythrocytes, commonly in the setting of extreme leukocytosis (> 10 x 10(4)/microl) or thrombocytosis (> 60 x 10(4)/microl). We report a case of pseudohyperkalemia in a patient with chronic renal failure and polycythemia vera without the finding of severe leukocytosis or thrombocytosis (white blood cell count 1.88 x 10(4)/microl and platelet count 37.9 x 10(4)/microl, respectively). The serum potassium concentration was 8.2 mEq/l, while the plasma potassium level was 6.4 mEq/l in a sample obtained simultaneously. The concentrations of platelet factor IV and beta-thromboglobulin, known to be markers of platelet activation, were greater than 100 ng/ml and 200 ng/ml, respectively, indicating that platelet activation may have been related to the development of pseudohyperkalemia in this patient. These findings suggest that pseudohyperkalemia should be considered when hyperkalemia is seen in a patient with chronic renal failure and myeloproliferative disorders.

Aged↗

PubMed2001

Effects of proteasome inhibitors on the synaptic localization of Vesl-1S/Homer-1a proteins.

The Vesl-1S/Homer-1a proteins are upregulated during seizure and long-term potentiation, but are rapidly degraded by ubiquitin-proteasome systems under normal conditions. We examined the distribution of Vesl-1S proteins in cultured hippocampal neurons. Application of proteasome inhibitors caused accumulation of Vesl-1S immunoreactivity in the neurons which showed a punctate distribution in the cortical regions of the cells, and these puncta were found to be juxtaposed with synaptophysin, a presynaptic, synapse-specific protein. These results suggest that Vesl-1S protein is synaptically targeted.

Acetylcysteine↗

PubMed2001

Duplication of 15q11.2-q14, including the P gene, in a woman with generalized skin hyperpigmentation.

We describe a woman with 15q11.2-q14 duplication who had clinical manifestations of proximal 15q trisomy and hyperpigmentation. Within this region, the P gene, located at chromosome segment 15q11.2-q12, is associated with oculocutaneous albinism type II (OCA2) and with hypopigmentation in the Prader-Willi and Angelman chromosome 15q deletion syndromes. We therefore hypothesized that in this woman skin hyperpigmentation might result from a duplication of the P gene. We carried out chromosomal and interphase fluorescence in situ hybridization (I-FISH) analyses, and determined that the P gene is duplicated in this woman. Our findings demonstrate that trisomy of the P gene can be associated with skin hyperpigmentation.

Carrier Proteins↗

PubMed2001

Expression of vesl-1S/homer-1a, a gene associated with long-term potentiation, in the brain of the epileptic EI mouse.

The El mouse is an animal model for hereditary epilepsy. It undergoes a convulsive seizure lasting 10-30 s after vestibular stimulation, such as "tossing-up". To better characterize the effects of seizure activity in the El mouse, we examined the expression profile of vesl-1S/homer-1a mRNA in the brain. It has been shown that this mRNA is expressed after long-term potentiation or seizures induced by electrical or pharmacological stimulations. The basal level of vesl-1S mRNA was very low even in seizure-susceptible El mice. The El mouse hippocampus, but not that of ddY mice, showed a remarkable increase in vesl-1S mRNA expression in the dentate granule cell layer after seizure induced by "tossing-up". The mRNA remained for about 3 h after the seizure and disappeared after 8 h.

Animals↗